Prevention of corrosion



Patented Mar. 9, 1954 UNITED STATE s PATENT- OFFICE PREVENTION OF CORROSION "Thomas G. Wisherd, Tulsa, Okla,

assignments, to Sinclair Oil and Gas as is y Company, Tulsa, Okla, incorporation of lilaine No Drawing. Application March a, 1951,

Serial No. 218,709

z Claims. (01. 252-855) 2 by conventional methods, displays favorable corrosion inhibiting properties when transported through connecting pipelines to the refinery.

The following example is offered to more clearly illustrate the efiectiveness of my ammonia ,neutralized sulfonated Neolene bottoms. -However it must be realized that the tests of the exmetallic equipment of practlcally all oil wells and in certain environments corrosion may reach costly proportions. The casing, tubing, sucker rods, and lead lines are particularly subject to corrosive effects. The sucker rods and sucker rod boxes which operate under hea'vy cyclic load repair or replacement'of rods, tubing and other equipment may also prove to be considerable.

Indirect costs in I have found that the corrosive effects of the well fluids on metallic surfaces can be substantially reduced, indeed in many cases practically eliminated, by introduction of an exceedingly minute'proportion of an oil-soluble ammonia neutralized sulfonated mixture of polyaikylated benzenes. The useful materials are derived from the bottoms from the production of dodecylbenzene- (Neolene) and hereafter are referred to as the ammonia neutralized sulfonated Neolene bottoms or the inhibitor. The ammonia neutralized sulfonated Neolene bottoms I use have" unexpected oil solubility and are prepared by the sulfonation-and subsequent ammoniation of the 'the casing. The effective proportion of my inhibitor is in the rangeapproximating 0.4 to 40 pints per one thousand barrels of well fluid. i. e.. crude oil and brine. The resulting crude produced from the well, after separation of the brine A, has the following test characteristics:

amples were run on a specific well fluid and that the'extreme variations found among well fluids and the rates and conditions of production of oil wells in the same and different fields are factors to be considered in drawing any conclusion therefrom. Also it is well known that a particular inhibitor may show superior anti-corrosive properties over those shown by'other corrosion inhibitors in a particular well or field and show inferior anti-corrosive properties to the same or other corrosion inhibitors in another jvell or field. Consequently oil well corrosion inhibitors are customarily selected for use in a particular well or field according to the conditions in that well or field, and even then-the superiority of a particular inhibitor over other inhibitors is unpredictable.

I compared the ammonia neutralized sulfonated Neolene bottoms with an oil solution of a commercially used sulfonate-type inhibitor. This inhibitor, which I shall refer to as Inhibitor v Gravity AP Flash F 385 Fire F 445 Viscosity at 100 SUS 416 Viscosity at 130 8118...; 163 Viscosity at 210 SUS' 49.2 Viscosity inde a 90 Color 4% Nitrogen, (percent) 0.265 Acid number p 9.0 Sulfur (percent) 0.60

Example! I compared-the ammonia neutralized sulfonated Neolene bottoms with Inhibitor A by that well fluid plus an inhibitor. The inhibitor concentration was based upon total fluid (crude oil plus brine). The well fluid used was a sour West crude oil composed of brine and 15%crude oil.

Inhibitor A Concentration,

Corrosion Wt. Percent 1 Rue (mad) ssssssssafi 1 Based In total fluid. Average of many tests.

Besides aflfording protection against corrosion, the ammonia neutralized sulfonated Neolene bottoms are characterised by considerable ease in handling and do not have any toxic or other injurious eiifects on personnel. Moreover, oil production is not interfered with, such as by the formation of lmdmirable clogging or contaminating materials either at the well or later at the refinery. Furthermore the essential ingredient of my composition, 1. e., the by-product bottoms from the manufacture of dodecylbenzene, and the materials for the treatmmt of the bottoms can be obtained commercially at low cost.

In the practice of my invention, I customarily dilute the acid sulfonated bottoms with isopropanol, water, and a non-volatile highly aromatic petroleum solvent before the neutralization with anhydrous ammonia. However, the amount and type of diluent added to the acid sulfonates prior tontlonisnotanessentialpartofthe productandmaybevariedasdesiredoreliminated aitirely depending upon the mode of using the suli'onates.

Tests and the compomtions of three typical concentrates follow:

ponillm Ash, Percmt AsIhave stated, the amounts of ammonia neutralised sulfonated bottoms employed are between 0.4 toiilpintsperthousand barrels of well fluid. Lessthantheminimumamountisgenerallyineflective in suhshmtially reducing corrosion etiectswhileover lilpintsperonebarrelsisandwastefuloftheinhibitor. sinc myamnmhneutralised sulfonated Neolenehottoumareresdilyoilsolubleandnotreadilywatersolublethegreaterportionisexpected to go into the crude oil rather than to remain in and to be drawn oi! with the brine. Some inhihitorkleftouwellmrfaceson thearrfacsofrmtcrothersuspendedsolidparticlmmmeklmtmthebrine. However.

4 oil well using two quarts of inhibitor and producing800barrelsofbrineand15barrelsofoil daily would be using 38 p. p. m. of inhibitor basedonwellfluidor800p.p.m.basedonoil. Generally, I contemplate treating .wells produci "sour" crudes, that is well fluids containing relatively large amounts of sulfur or sulfur compounds, since such wells prment the most severe corrosion problems.

The actual amount of inhibitor employed within the above range is ordinarily directly related to the corrosiveness of the well fluid, the resistance of the metallic surfaces to corrosion and the production rate. In particular, flow interruptions and varying temperatures and pressures are capable of aflecting corrosion considerably. Of course the actual measure of corrosion. and

therefore regulation of inhibitor concentration,

can be determined in-the last analysis by the actual deterioration in the physical condition of .the metallic surfaces involved. However, it may not be practical to rely on such visual inspections since the damage is then already effected. According y, metal test blanks may be used for insertion into the well fluid stream and removed and examined at periodic intervals. Direct measurement of the well fluid acidity is also possible.

Or a measure of the iron content may be made The bottoms from the production of dodecylbenzene which I employed in producing this particular concentrate were Neolene 400 Bottoms obtained commercially from Sharples-Continental Corporation. Typical physical properties of "Neolene 400 Bottoms" are as follows:

Engler range:

18? TL. 644 1% IL- 671 2 T... 685 8 "F" 690 4 F... 695 5 '1"..- 698 20 FL- 723 T... 739 l" 753 FL. 775 92 "FL. 777 93 "F" 778 94 "F..- 779 96 F.... 780 97 TL. 780 98 F 780 F3? F 780 Percent rec. F 99 Spec. gravity at 100 F. 0.8639 Spec. gravity at F. 0.8545 Viscosity in centipoises at 130 F. 45.8 Color Dark brown Molecular weight 403x15 "Neolene 400 Bottoms were charged in the amount of 1888 pounds to a conventional type llonel sulfonator and sulfonated by the addition of commercial 20% oleum totaling 1782 pounds. The mass m agitated continuously during the its concentration in crude oil can be relatively addition of the oleum and the temperature was highastheoilispumpcdthroughcrudelines heldtoamaximumof147Ebythecirculation after scparatlm of the brine. For example, an 75 of cooling water through continuous coils located in the acid mass, and by the rate of oleum addition. The total time required for oleum application was 50 minutes.

The acid mass was next washed by the gradual application or 1335 pounds 01' water. Agitation was continued during the washing operation and until the sulfonated bottoms-diluted acid mass was pumped to the settler. Due to the heat evolved :by dilution of the partially spent oleum during the washing operation the temperature rose rapidlyi' The washing temperature was held to a maximum oi 196 F. by controlling the rate of addition of the water and by means of the cooling coils. The time required for the washing operation was 90 minutes and the final temperature was 185' F. The washed sulfonated mixture was then pumped to a glass-lined, water-jacketed settling tank which had been brought to 185 F. by injecting steam into the water in the Jacket. mass was allowed to settle without any further application of heat for a period of 16 hours; At the end of the 16 hour settling period the temperature of the mass was 152 F.

The diluted acid was now drawn from the bottom of the settler and discarded. The acid sulfonates, containing only a small amount of dilute sulfuric acid, were drawn to a neutralizing vessel and diluted with 18 gallons of 99% isopropanol, 18 gallons of water, and 35 gallons of non-volatile,

The

highly aromatic petroleum solvent. The diluted acid sulionates were neutralized by the addition of 122 pounds ofanhydrous ammonia, and the finished product drawn to drums for storage. The yield was 356 gallons. The material produced by troducing into the stream of well fluid ammonia neutralized sulfonated bottoms produced in the manufacture of dodecylbenzene which bottoms consist essentially of didodecylbenzene and other polyalkylated benzenes in the amount of 0.4 to pints per thousand barrels of well fluid.

2. Crude oil to which favorable rust inhibiting properties have been imparted by the addition of 0.4 to 40 pints per one thousand barrels of well fluid of ammonia neutralized sulfonated bottoms from the production of dodecylbenzene which bottoms consist essentially of didodecylbenzene and other riolyalkylated benzenes.

THOMAS G. WISHERD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,422,515 Anderson Jun 17, 194'! 2,509,786 Sehiermeier et al. May 30, 1950 2,545,138 Chester Mar. 13, 1951 

1. IN THE PRODUCTION OF OIL FROM WELLS WHEREIN A STREAM OF WELL FLUID IS WITHDRAWN FROM AN OIL WELL IN CONTACT WITH METALLIC SURFACES, THE METHOD OF REDUCING THE CORROSIVE EFFECT OF SAID WELL FLUID UPON SUCH METALLIC SURFACES WHICH COMPRISES INTRODUCING INTO THE STREAM OF WELL FLUID AMMONIA NEUTRALIZED SULFONATED BOTTOM PRODUCED IN THE MANUFACTURE OF DODECYLBENZENE WHICH BOTTOMS CONSIST ESSECTIALLY OF DIDODECYLBENZENE AND OTHER POLYAKYLATED BENZENES IN THE AMOUNT OF 0.4 TO 40 PINTS PER THOUSAND BARRELS OF WELL FLUID. 